1. Field of the Invention
The present invention relates to a method of and an apparatus for synchronizing reproduction using a plurality of video information reproducing systems, and, more particularly, to a method of and an apparatus for synchronization in reproducing video information recorded in a plurality of video information reproducing systems by synchronizing said video information.
2. Description of the Prior Art
A synchronizing system of this type is adopted in a system for reproducing a plurality of items of video information on a plurality of screens by synchronizing said video information, such as a multi-screen display system. If video tape recorders are used as reproducing systems, this type of multi-screen display system is arranged such that, after temporarily stopping each video tape recorder at a position represented by a program search mark recorded on a tape, all the video tape recorders are restarted simultaneously from these positions. Incidentally, a system similar to the above-described prior art is disclosed in Japanese Patent Laid-Open No. 150160/1982. In such a system, in order to eliminate discrepancies in synchronization resulting from differences in the rise characteristics of reproducing systems, the following arrangement is generally adopted. By supplying from the outside a synchronization signal which serves as a reference, the phase difference between the synchronization signal and a reproduction synchronizing signal is detected, and motor rotation servo systems of the reproducing systems are so controlled that the phase difference becomes zero.
Meanwhile, if video disk players are used as reproducing systems in the aforementioned multi-screen display system, a CAV-type disk with a constant angular velocity is employed, each pickup is temporarily stopped at the position of a required video frame number, and synchronization is obtained by simultaneously starting the video disk players after placing all the pickups at the same position.
If video tape recorders are used as reproducing systems in the aforementioned multi-screen display system, a troublesome procedure is required in which, after the reproducing systems have been temporarily stopped, they are restarted, and synchronization is finally adjusted by an external synchronizing system. On the other hand, if video disk players are used as reproducing systems, there are no discrepancies in synchronization resulting from differences in rise characteristics in the case of a CAV-type disk, unlike video tape recorders, so that no external synchronizing system is required. Nevertheless, there is one problem that remains unsolved which is that after the video disk players have been temporarily stopped, they need to be restarted started simultaneously from the same position.
For this reason, in the case of disks in which pickups cannot be stopped temporarily midway through a disk like a CLV-type disk (a long-playing disk) whose linear velocity at the pickup position is constant, it is impossible to effect synchronization and this has been a significant problem.